Watermill generator

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Watermill generator

Watermill generator

Produces electricity from a river. Must be placed with its wheel in moving water. If watermills are placed too close together, the turbulence they generate will interfere and reduce power generation.

Base Stats

Market Value
600 Silver [Note]


5 ˣ 6
Cover Effectiveness
Blocks Wind
1100 W


Required Research
Watermill generator
Skill Required
Construction 6
Work To Make
4,000 ticks (1.11 mins)
Resources to make
Wood 280 + Steel 80 + Component 3
Deconstruct yield
Wood 140 + Steel 40 + Component 1 - 2
Destroy yield
Wood 70 + Steel 20 + Component 0 - 1

Watermill generators are built on moving water to generate a constant 1100W of power, regardless of weather or other conditions.


Watermill generators can be constructed once the Watermill generator research project has been completed. They require Wood 280 Wood, Steel 80 Steel, Component 3 Component, 4,000 ticks (1.11 mins) of work, and a Construction skill of 6.


The watermill generator produces a constant 1100W after construction. The watermill generator is unique in that it requires two different types of terrain: heavy terrain (i.e. solid ground, not mud or gravel) and moving water (shallow or deep, so "creeks" work just as well).

The base is a 3x3 square in the middle of the housing; the housing extends another 1 square beyond that, making a 5x5 square. Then the 1x5 waterwheel is attached to one side of the housing (your choice), making the total footprint 5x6. Only the 3x3 base must be on firm ground, the rest of the housing may be over water. (See images, below)

A watermill generator must be placed:

  1. with its 3x3 base on tiles that can support Heavy (i.e. on solid ground, not on a bridge or marsh)
  2. with its water wheel entirely in moving water
  3. with neither its housing nor wheel overlapping any other buildings or walls
  • Bridges do not interfere with power generation if built within the generator's exclusion zone.

When placing the watermill generator, the blueprint will show:

  • The 3x3 base of the generator (in white)
  • The 5x5 housing of the generator (green if placeable, red if not)
  • The 1x5 waterwheel of the generator off one side of that (green if placeable, red if not)
  • The (semi-)exclusion zone, explained below (blue on previously built watermills, green if OK, flashing orange if overlapping)


Power output does not depend on water tiles covered. However, the output of watermills will be reduced to 30% (330W) if you overlap their exclusion zones. The exclusion zones are 13x7 rectangles, extending 4 squares above, below and outside the mill. If you wish to build multiple maximally efficient watermills, they will need to be spread out a bit, making them slightly harder to defend than most other power generating systems.

The 70% reduction does not stack, so given a sufficiently straight river, an alternative strategy to maximize power output would be to cram as many watermill generators as possible along both sides of the river bank. However, at -70% penalty, building 3 would only be 90% of the power of building just one with a clear exclusion zone, and 4 would only be a 20% increase vs. that first one. It would take a very cooperative, straight section of river, and at least 8 watermills, 4 on each side, all side by side, to start to rival the 2,200W output of just 2 well-spaced watermills (and in just over the space required by 2).

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